There was a certain irony in the fact that, on the weekend President George Bush died, the 45th president of the United States was attending an international conference where his principal efforts seemed aimed at key elements in the New World Order the 41st president sought to build.

While keeping a relatively low profile at the G-20 summit in Argentina in hopes of avoiding the gaffes that marked several prior international ventures, Trump did two things, both of which exemplified the contrast between his policies and those of the Bush presidency three decades ago: replacing the Western Hemispheric agreement that became known as NAFTA and seeking to redirect U.S. policy toward China.

Trump, who made it a presidential goal to scrap the "terrible" North American Free Trade Agreement, joined the prime minister of Canada, Justin Trudeau, and the outgoing president of Mexico, Enrique Pena Nieto, in signing what he called the "groundbreaking" USMCA (the U.S.-Mexico-Canada Agreement), really a modest revision some termed NAFTA 2.0.

Though signed under President Bill Clinton, the NAFTA agreement was very much the work of Bush and his predecessor, Ronald Reagan.

Then, Trump reached at least a short-term truce in the trade war he launched against China in pursuit of another of his signature initiatives, curbing the Asian power's economic expansionism in the interest of an America First policy that is at sharp odds with the more cooperative global outlook of not only Bush but the other former presidents who joined in mourning him this week.

It was Bush who made certain the U.S.-China relationship continued and prospered after the Beijing government brutally quashed pro-democracy forces in Tiananmen Square.

Throughout this week, much has been written of the personal differences between the sometimes self-effacing, steady and experienced Bush, who guided the world through the tumultuous end of the Cold War, and the brusque, self-promotional governmental neophyte Trump, who makes a goal of disrupting existing norms.

But the policy differences Trump has instituted, especially in foreign policy, could well prove more consequential than the contrasts in their personal styles when he turns over the presidency to his inevitable successor, be he or she Democrat or Republican.

A lot will depend on whether, for example, the current cease-fire in the US.-China tariff war leads to a mutually beneficial agreement or whether, after the 90-day truce, it resumes to the detriment of the economies of both countries. Already, it seems, that concern is one reason the two sides stepped away last weekend from the economic abyss.

In a broader sense, U.S. relations with its longtime global allies — as well as with major rivals like Russia — may depend on the extent to which Trump succeeds in weakening three-quarters of a century's U.S. military and economic ties with Western Europe as he pursues friendlier relations with Russia's Vladimir Putin.

In one area, Trump has already done substantial damage: abandoning the U.S. role established by prior presidents — be they more realistic or idealistic — as a beacon of democracy for nations around the world.

In refusing to condemn Putin, effusively praising other autocratic leaders, and giving the benefit of the doubt to Saudi Arabia's Mohammed bin Salman in the murder of Jamal Khashoggi, Trump has conceded the moral high ground the United States has always occupied.

And his overall withdrawal from U.S. international primacy stands in abrupt contrast to the two signal acts of leadership for which George Bush's presidency will most be remembered: presiding over the peaceful end of the Cold War and the subsequent collapse of the Soviet Union, and forming the global coalition that drove Iraq's Saddam Hussein from Kuwait while avoiding the troubles that later bedeviled his presidential son.

Bush played a central role forging the 1990 reunification of Germany, an essential development that has led to three decades of European stability, after he showed on the day the infamous Berlin Wall fell that leadership does not always mean cheering your adversaries' defeat.

Then, he used the relationships developed over two decades of international experience to build the multi-national alliance that achieved swift success, just seven months after Hussein seized his wealthy, oil-rich neighbor. Despite some domestic political demands to continue the military campaign into Iraq and overthrow Hussein, Bush stopped at the border, noting that's what he promised his coalition partners.

A few years later, he joined with his national security adviser, Gen. Brent Scowcroft, in a book that warned how ousting the Iraqi leader would have made the United States "an occupying power in a bitterly hostile land" and "incurred incalculable human and political costs." They seemed prescient, when precisely that happened after President George W. Bush overthrew Hussein.

It's likely that neither the peaceful end of the Cold War nor the successful liberation of Kuwait would have been possible with the current chief executive's mindset and style.

Carl P. Leubsdorf is the former Washington bureau chief of The Dallas Morning News and a frequent contributor. Email:carl.p.leubsdorf@gmail.com